Climate science right

Piers Corbyn (Letters, July 24) is wrong in his claim that "there is no evidence that CO2 is a net driver for world climate". CO2 absorbs and emits infrared radiation. This can be measured in the laboratory. It can be measured by pointing instruments at the sky. And the emission, and effects of its absorption, is measured continuously by weather satellites orbiting the Earth. Mr Corbyn's logic appears to be that because the variations in the sun can impact on climate (a fact not seriously disputed within the climate-science community), no other factor can influence climate. But if the 22-year magnetic cycle of the sun's activity is really "the most significant and persistent cycle of variation in the world's temperatures", just why have recent global-average temperatures been around 0.4 degrees warmer than they were in the early 1980s, unless one invokes other causes? Professor Keith Shine Department of meteorology, University of Reading